There are known displays implemented in the form of a flat cuvette formed by two parallel glass plates, the inner sides of which feature electrodes, made of optically transparent conducting material, and orienting layers. After assembling the cuvette it is filled with liquid crystal, which forms a layer 5–20 μm thick and acts as the active medium, changing its optical properties (the angle of rotation of the polarization plane) under the influence of an electric field. The change of optical properties is registered in the crossed polarizers, which are usually glued onto the outer surfaces of the cuvette. Therein, areas of the display where electrodes are not under the voltage will transmit light and look bright, whereas the areas under voltage will look dark [L. K. Vistin. JVHO, 1983, vol. XXVII, ed.2, pp.141–148].
The major drawbacks of the mentioned displays are the limited speed, low contrast of imaging and small observation angle, since the multilayer design of the LC-display is effectively governed by the flow of light propagating within the limited solid angle relative to normal to the surface of the display.
As polarizers in such displays one usually uses polarizers based on uniaxially stretched polymer film (for example, polyvinyl alcohol) dyed with iodine vapors or an organic dye [U.S. Pat. No. 5,007,942]. Polarizing effectiveness of such films is determined by the concentration of iodine or other dye in the polymer film and the degree of orderliness of the polymer chains.
Such films possess the so-called positive dielectric anisotropy and positive dichroism. This means that the dipole moments of the optical transition of molecules responsible for absorption of light are oriented along the direction of stretching. Therein, the ellipses of angular dependence of the real and imaginary parts of the refraction index have elongated (needle-like) form. Polarizers obtained from the said films represent polarizers of the O-type, since they transmit the ordinary wave, while absorbing the extraordinary one.
Despite the high polarizing effectiveness of polarizers obtained from the said materials, they feature significant drawbacks, some of which are their light and thermal stability, the necessity to fabricate films of significant thickness in order to provide the high effectiveness. One of the major drawbacks is the fact that two cross oriented polarizers have significant transmission of light incident at an angle to the surface of the polarizer, especially in the directions azimuth of which is ±45° relative to the axis of polarization.
There is a known LC-display with internal polarizers [RU 2120651]. As polarizers in this LC-display one uses thin crystalline films of molecularly ordered structure of organic compounds—dyes [U.S. Pat. No. 5,739,296]. The flat molecules of dyes are grouped into aligned clusters—supramolecular complexes. The planes of molecules and the laying in them dipole moments of optical transition are oriented perpendicularly to the axis of macroscopic orientation of the obtained film. In order to create such structure, one uses the liquid crystal state of the dye, where molecules already posses local orderliness, while being in the one- or two-dimensional quasi-crystalline aggregates oriented relative to each other. When depositing such system onto the substrate and simultaneously applying external orienting influence, this film assumes macroscopic orientation, which in the process of drying the solution, not only remains intact, but may also enhance due to crystallization effect. The axis of polarization, then, is directed along the orienting influence, coinciding with the direction of deposition of the polarizer. In this case, ellipses of angular dependence of the real and the imaginary parts of the refraction index have disk-like shape.
These polarizers represent the E-type polarizers, since they transmit the extraordinary wave while absorbing the ordinary one. The said polarizers feature good angular characteristics, they are light- and thermally stable, they are applicable for forming structures of displays according to the thin-film technology, due to which they appear to be promising in the display technology.
Since in the recent time the main objective in fabrication is miniaturization of devices, the starting point task in fabricating the above displays is the issue of decreasing dimensions of the separate parts of the device as well as the concomitant functional elements, ensuring their functionality. The above polarizers and other anisotropic films based on them are widely utilized in portable displays of various purposes. One of the major challenges arising in fabrication of miniature displays is the decrease of size of their power supplies, which instigates decreasing power consumption and increasing effectiveness of using the governing electric field in the display. Losses of power are due to the low conductivity of the transparent electrodes as well as the voltage drop across the intermediate layers between electrodes and the layer of liquid crystal.
There are various known ways of increasing conductivity of the transparent electrodes, which are usually made of indium-tin oxides, featuring insufficient conductivity. Thus, they may be annealed at about 250° C. [U.S. Pat. No. 6,198,051]. It is also possible to create an auxiliary electrode structure, which is made of highly conductive materials, either on a part of the surface of the transparent electrodes in the form of solid lines or on the entire surface of electrodes in the form of cellular coating [U.S. Pat. No. 6,198,051].